The present invention relates to electrochemical capacitors with a double electric layer (DEL), and can be used in the production of electrochemical capacitors with a DEL. A proposed electrode with a DEL based on non-metal conducting materials, including porous carbon materials, is capable of providing for electrochemical capacitors with high specific energy, capacity, and power parameters, as well as low cost. Electrodes according to the present invention can be used as positive and/or negative electrodes of symmetric and asymmetric electrochemical capacitors with aqueous or non-aqueous electrolytes.
Recently, carbon materials have increasingly attracted the attention of both theoreticians and experimentalists due to the great number of unique properties which properties make it possible to widen the scope of their practical application. Manufacture of electrodes for electrochemical capacitors is one of the most promising directions for extensive use of such carbon materials. The research of physical, electrical, electrochemical and other properties of activated carbon materials for their effective use in electrochemical capacitors with aqueous and organic electrolytes has resulted in considerable development of the technology of synthesis and improvement of different parameters of carbon materials. However, many theoretical calculations show that the currently achieved level of energy, capacity and operational parameters of the best examples of modern electrochemical capacitors based on carbon materials are limited by performance capabilities of the carbon materials. It is possible, however, to control in a wide range the fundamental properties of carbon materials (including those ones which are important for electrochemical capacitors) by means of their doping by different elements, thereby allowing for a considerable step forward on the path to the improvement of electrochemical capacitors' parameters.
The electrical, electrochemical and physical properties of carbon materials which determine the main parameters of the electrochemical capacitors in which they are used are closely related to the concentration and type of impurity atoms present, structural defects of the crystal lattice, and the dimensions and form of the carbon particles. The activated carbon materials that are used in the manufacture of electrodes of modern electrochemical capacitors usually contain a great number of structural defects and are not pure substances. The quantity and type of impurity atoms may vary from several ppm to several percent. Many impurity atoms are contained in the initial materials, and partially penetrate the carbon materials during their synthesis. Certain impurities during the synthesis of carbon materials are deliberately used as catalysts to influence the process of graphitization and modification of parameters and the condition of the surface of carbon particles. This results in an increase of the concentration of uncontrolled impurities in carbon materials. The presence of different types of uncontrolled impurity atoms in the crystal lattice may considerably change important properties of carbon materials, which can have a negative effect on the parameters of subsequently constructed capacitors. This is one of the major causes of low specific energy, capacity and power parameters of electrochemical capacitors with carbon electrodes.